Lithographic Collector Alignment via Reflective Region
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Solution Overview
Problem
Existing lithographic apparatuses face challenges in accurately aligning collector devices due to environmental harshness and misalignment issues, particularly with light emitting diodes (LEDs) being prone to damage from high temperatures and EUV radiation, making precise and durable alignment difficult.
Innovation Solution
A system that includes a detector in a fixed positional relationship with the illumination system, using a region on the collector to redirect radiation and detect changes in its orientation or position, eliminating the need for LEDs by utilizing existing radiation sources to align the collector with the illuminator, ensuring accurate and durable alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If LEDs are attached to the collector for alignment measurement, then alignment precision can be improved, but the reliability deteriorates due to damage from high temperatures and EUV radiation
Solution Approach 1:
The patent introduces a reflective region on the collector as an intermediary element. Instead of attaching LEDs directly to the collector (which damages them), the system uses existing radiation from the source that reflects off the collector's reflective region. This reflective region acts as a mediator that carries alignment information without being damaged by the harsh environment, thus improving measurement precision while maintaining reliability.
2Ease of operation
If LEDs are used for alignment, then alignment can be performed, but the device complexity increases due to attachment requirements and drift issues
Solution Approach 1:
The patent makes the collector self-service for alignment purposes. The collector already has reflective regions that are part of its normal structure, used for directing radiation. By utilizing these existing reflective regions and the radiation already present in the system, the alignment function is achieved without adding separate LED components, mounting structures, or complex attachment mechanisms. This eliminates drift issues and reduces device complexity while maintaining alignment capability.
3Measurement precision
If the collector is realigned after movement or replacement, then alignment accuracy can be restored, but the loss of time increases due to realignment procedures
Solution Approach 1:
The patent enables preliminary alignment verification to be performed immediately after collector movement or replacement. By using the reflective region and existing radiation source, the alignment status can be quickly checked and adjusted without waiting for LED components to be attached and calibrated. This preliminary action capability restores alignment accuracy much faster, reducing the time loss associated with realignment procedures.
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This solution provides a robust and accurate method for aligning the collector device with the illuminator, improving alignment precision and durability by eliminating the reliance on LEDs, thus overcoming environmental damage concerns and maintaining alignment over time.
Implementation Method 1
the detector being arranged to detect a change of a characteristic of the portion of radiation, such a change being indicative of a change in a position or orientation of the collector
Implementation Method 2
a region of the collector configured to direct a portion of radiation emanating from the radiation source and traversing the region toward the detector
Data Source
AI summary
A lithographic apparatus (2) can include a radiation source (SO) configured to provide radiation (200), a radiation collector (CO) configured to collect radiation (200) from the radiation source (SO), an illumination system (IL), and a detector (300). The detector (300) can be disposed in a fixed positional relationship with the illumination system (IL) relative to an alignment of the collector (CO). Further, a region (310) of the collector (CO) can be configured to direct a portion of radiation (200) emanating from the radiation source (SO) and traversing the region (310) towards the detector (300). The detector (300) can be configured to detect a change in a portion of the radiation (200). The change can be indicative of a change in position or orientation of the collector (CO) relative to the illumination system (IL) relative to an alignment of the collector (CO).